1. Field of the Invention
Embodiments of the invention relate to smart cards. More particularly, embodiments of the invention relate to smart cards adapted to operate a mixed mode including both contact and contactless modes.
This patent application claims priority to Korean Patent Application 2005-15493 filed Feb. 24, 2005, the subject matter of which is hereby incorporated by reference in its entirety.
2. Discussion of Related Art
The term “smart card” generally refers to a well known class of portable tokens, variously embodied but characteristically comprising at least one integrated circuit (IC) (e.g., a “smart card chip”). Smart cards may be classified in relation to their mode of operation, including generally a contact mode, a contactless mode card, and a mixed mode.
Contact mode smart cards are commonly configured with a so-called subscriber identification module (SIM) and are adapted to operate using power voltages (e.g., source and ground), clock signal(s), a reset signal, and/or data signals electrically provided through connection pins (e.g., contact terminals) included in the smart cards' form factor. For example, a related host device may provide the foregoing signals once the smart card is input to the terminal.
In contrast, contactless mode smart cards are adapted to operate by “abstracting” the power voltages, clock signal(s), reset signal, and data signals from radio frequency (RF) signals received in the smart card through an integrated antenna.
Not surprisingly, mixed mode smart cards are adapted to operate in either contact or contactless modes. Thus, mixed mode smart cards typically include contact pins adapted to engage an external terminal during operation in a contact mode, and an antenna adapted to receive externally provided RF signals during operation in a contactless mode.
FIG. 1 is a block diagram of a conventional smart card system 100 operable in mixed mode. Referring to FIG. 1, smart card system 100 comprises a smart card chip 110, contact terminals 120 to supply voltages, signals, and data to smart card chip 110 in the contact mode, and contactless terminals 130 and 140 to supply voltages, signals, and data to smart card chip 110 in the contactless mode.
In contact mode, smart card system 100 communicates with a host device while being supplied of power voltages, clock signal(s), reset signal, and data signals through contact terminals 120. On the other hand, in contactless mode, smart card system 100 communicates with a host device, by abstracting power voltages, clock signal(s), reset signal, and data signals from RF signals received through contactless terminals 130 and 140.
However, the conventional smart card system as shown in FIG. 1 has a problem related to re-initializing its internal circuits. The problem may occur, for example, when a first ongoing smart operation (either contact or contactless) is interrupted by a second smart card operation made using the alternate mode of operation. For example, the re-initializing problem may occur when during a contact mode of operation (e.g., attempting to pay a bus or subway fare) is interrupted by a contactless mode of operation (receiving an incoming mobile phone call).